You can make this recipe with impeccably fresh oysters of any variety. I live in the northeast of the U.S., where we're very lucky to have quite a few large, briny, hyper-local varieties. I'd recommend learning about your own local options, if any, and otherwise buying from a purveyor you trust. Butter plays a big role in this recipe, so use a good one. I always try to use a cultured, salted butter from grass-fed cows. This sounds fancy but doesn't have to be. Kerrygold, for example, is sold at many supermarkets in the U.S. for a reasonable price and ticks all the boxes. For the fresh herbs, I've suggested a combination of basil and parsley — but you can substitute or incorporate other soft leafy herbs that complement seafood, like dill, chervil, chives, sorrel, or even a little bit of thyme. You can shuck the oysters, prepare and apply the shallot herb butter, and prep the prosciutto and lemon juice a few hours in advance. Arrange the oysters in the pan, cover tightly, and refrigerate. Right before serving, fire up the oven, bake the oysters, and add the final toppings. Leftovers will keep in an airtight container in the fridge for a few days. You can store them in the shells or decant them into an airtight container and toss with pasta. Rewarm over low heat so you don't overcook the oysters.